slack.com website review

17 images could be 3.1 MB smaller with modern formats (WebP or AVIF) and sizes that fit a phone screen. Google estimates it would make the page about 1.2 s faster on a phone.

11 files block the first paint until they finish downloading. Deferring or inlining them could save about 2.8 s.

Google Tag Manager costs a phone 1.5 s of main-thread work and 705 KiB of downloads while your page loads. That alone is enough to make taps feel slow. Loading it after the page is usable, or only on the pages that need it, takes that off the critical path.

Your mobile performance score is 42 (desktop: 63). Under 50 is Google's “poor” band: many phone visitors leave before the page is usable.

A phone's processor spends 5.8 s on main-thread work while loading, 3.2 s of it running JavaScript. Above 2 s, taps and scrolls feel sluggish.

8 third-party services load with your homepage (Google Tag Manager, YouTube and slack-edge.com and others), adding 58.9 MB and 2.7 s of main-thread time.

slack-edge.com costs a phone 258 ms of main-thread work and 56.7 MB of downloads while your page loads. Loading it after the page is usable, or only on the pages that need it, takes that off the critical path.

About 1.2 MB of JavaScript is downloaded but never used on this page.

18 long tasks block the main thread while loading, the longest for 736 ms. During a long task the page ignores taps.

YouTube costs a phone 595 ms of main-thread work and 990 KiB of downloads while your page loads. Loading it after the page is usable, or only on the pages that need it, takes that off the critical path.

About 217 KiB of CSS is downloaded but never applied on this page. Google estimates it would make the page about 300 ms faster on a phone.

The page has 2,144 HTML elements. Above 1,500, rendering and every interaction get slower on phones.

16 files are served with short cache lifetimes, so returning visitors download them again (156 KiB).

Polyfills for old browsers add 30 KiB JavaScript that modern phones do not need.

Critical files load one after another instead of in parallel (3 chains). Preconnecting to key origins and preloading the hero image shortens the chain.

Scripts make the browser recalculate the layout repeatedly while the page loads, which wastes processor time on phones.

Real Chrome users on phones do not pass Google's Core Web Vitals on this page (28-day field data from the Chrome UX Report (opens in a new tab)). Google uses this in ranking.

The page becomes fully interactive after 28.4 s. Good is under 3.8 s.

Scripts block taps and scrolling for 1.7 s in total while the page loads. Good is under 200 ms.

Your largest element takes 5.5 s to render on a phone. Google's threshold for “good” is 2.5 s. The largest element is the element shown below.

The first text or image appears after 3.2 s on a phone. Good is under 1.8 s.

Real visitors wait 2.6 s for the largest content to appear (75th percentile). Good is under 2.5 s.

Real visitors wait 272 ms for the page to respond to a tap (75th percentile). Good is under 200 ms.

Real visitors see the first content after 1.9 s (75th percentile). Good is under 1.8 s.

Real visitors wait 826 ms for your server to start answering (75th percentile). Good is under 800 ms.

46 images have no width and height attributes, so the layout jumps as each one loads.

Visually, the page fills in at 4.7 s (Speed Index). Good is under 3.4 s.

Over the last 25 four-week periods to 2026-10-03, real Chrome visitors' tap response (inp) went from 248 ms to 270 ms at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Over the last 25 four-week periods to 2026-10-03, real Chrome visitors' largest content (lcp) went from 2.8 s to 2.8 s at the 75th percentile (Chrome UX Report (opens in a new tab) history).

Your homepage downloads 59.2 MB in 216 requests on a phone: media 51.2 MB (33), images 5.0 MB (63) and scripts 2.4 MB (43). Under 2 MB keeps phones on slow connections fast.

2 images (143 KiB) are JPEG, PNG or GIF. The same pictures as WebP or AVIF are usually much smaller at the same quality, and every current browser shows them.

By the Sustainable Web Design model, a visit to your homepage emits about 16.79 g of CO₂e: 2014.5 kg a year at 10,000 visits a month. It scales with page weight, so every byte cut lowers it.

9 tap targets are too small or too close together to hit reliably with a finger.

All page content should be contained by landmarks: 1 element on the page fails this check, rated moderate by axe-core.

The skip-link target should exist and be focusable: 1 element on the page fails this check, rated moderate by axe-core.

Elements marked as presentational should be consistently ignored: 30 elements on the page fail this check, rated minor by axe-core.

No structured data (JSON-LD), so Google can't show rich results such as your logo, ratings or FAQs.

Your meta description is 173 characters; Google truncates after about 160, so the end of your pitch is cut.

1 link use generic text like “click here” or “learn more”, which tells Google nothing about the page behind it.

The homepage links to 267 pages on slack.com and 29 external pages.

There is no Organization (or LocalBusiness) JSON-LD, so search engines and AI assistants have no machine-readable facts about who runs the site: its name, logo, profiles and contact details.

Your homepage links to /features/clips, /features/crm, /features/crm/small-business, /features/templates, /features/canvas and /features/task-list and 5 others, which answer with an error. Visitors hit a dead end and search engines drop them.

We fetched 15 pages linked from your homepage (of 94 found) and read each the way a search engine does.

1 image failed to load on a phone, for example https://id.rlcdn.com/464526.gif.

2 third-party cookies are set on load; browsers are restricting these, so whatever relies on them breaks.

1 error was logged to the browser console while the page loaded, for example “Failed to load resource: net::ERR_FAILED”.

Chrome logged issues while loading the page (“Cookie”).

15 links from your homepage to your own site are broken, for example https://slack.com/features/crm (404).

No Content-Security-Policy header, the main browser-side defence against injected scripts.

X-Content-Type-Options: nosniff is missing, so browsers may guess file types.

1 link go through two or more redirects, for example https://facebook.com/slackhq.

No Permissions-Policy header to switch off camera, microphone and location for embedded content.

No phone number or email link on the homepage, so ready-to-buy visitors have one fewer way to reach you.

There is no form on the homepage, so every lead has to click through to another page first.

No guarantee or risk reducer (money-back, free trial, no credit card) is mentioned, which is often what tips a hesitant visitor.

The homepage carries about 1,024 words of visible text.

We found no DKIM key on the selectors the big email providers use. If you send through one of them, turning on DKIM signing improves delivery.

Email authentication: SPF record 25 points, plus 15 when it ends in -all (10 for ~all); DMARC record 25, plus 25 for a reject policy (15 for quarantine); a DKIM key on a common selector 10.

Before a visitor clicks anything, the page loads Google Ads, Google Analytics, Google Tag Manager, LinkedIn Insight and Reddit Pixel (measured from a US location before any click). A consent tool (OneTrust) is installed; check it blocks these until visitors agree where the law requires it.

Opening the homepage sets 20 cookies, 4 of them by other companies (measured from a US location before any click).

Loading the homepage contacts 43 hosts run by other companies (fonts, scripts, analytics, ads), each of which sees the visitor's IP address.